The World of Warcraft PTRs have brought some interesting new class changes for the Druid, Mage, and Shaman. Blizzard seems to have changed the Druid's Regrowth, the Mage's Blink, as well as reworked the tooltip description on Shaman's Toughness.

Druid
Regrowth mana cost has been reduced, the new values are (from rank 1 to rank 9):           
rank 1 - 80 (was 100)
rank 2 - 135 (was 170)
rank 3 - 185 (was 230)
rank 4 - 230 (was 285)
rank 5 - 275 (was 345)
rank 6 - 335 (was 420)
rank 7 - 405 (was 505)
rank 8 - 485 (was 605)
rank 9 - 575 (was 720)
rank 10 - 675 (was 845)

Mage

Blink mana cost changed, it's now 21% of base Mana instead of 28% (live). (It was 15% of base mana in the previous build)

Shaman
Toughness (tooltip description changed) -

Old: Increases your armor value from items by 2/4/6/8/10%, and reduces the duration of movement impairing effects on you by 10/20/30/40/50%.

New: Increases your armor value from items by 2/4/6/8/10%, and reduces the duration of movement slowing effects on you by 10/20/30/40/50%.

All in all, these are some nice buffs for the druid and the mage, and the Shaman gets some clarity on the bug that was mentioned a few days back. Keep checking QJ for more updates as they happen.